This might be of importance:

$ atactl wd0 smart error-log    
SMART supported, SMART enabled
No errors have been logged
$ atactl wd1 smart error-log 
SMART supported, SMART enabled
Log entry: 1
    Command 0: dc=02 sf=00 sc=01 sn=01 cl=00 ch=00 dh=a0 cmd=10 time=00d9a33c
    Command 1: dc=02 sf=03 sc=0c sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9a33c
    Command 2: dc=02 sf=03 sc=46 sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9a33c
    Command 3: dc=02 sf=00 sc=10 sn=00 cl=00 ch=00 dh=a0 cmd=c6 time=00d9a33c
    Command 4: dc=00 sf=00 sc=20 sn=df cl=b3 ch=18 dh=e2 cmd=c8 time=00d9a33c
    Error: err=84 sc=00 sn=fe cl=b3 ch=18 dh=e2 status=51 state=03 lifetime=0005
    Extended: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Log entry: 2
    Command 0: dc=00 sf=00 sc=80 sn=a0 cl=82 ch=3a dh=e9 cmd=ca time=00d9cd6c
    Command 1: dc=00 sf=00 sc=60 sn=1f cl=84 ch=29 dh=e2 cmd=c8 time=00d9cd6c
    Command 2: dc=00 sf=00 sc=60 sn=ff cl=85 ch=29 dh=e2 cmd=c8 time=00d9cd6c
    Command 3: dc=00 sf=00 sc=80 sn=20 cl=83 ch=3a dh=e9 cmd=ca time=00d9cdd0
    Command 4: dc=00 sf=00 sc=20 sn=5f cl=86 ch=29 dh=e2 cmd=c8 time=00d9cdd0
    Error: err=84 sc=00 sn=7e cl=86 ch=29 dh=e2 status=51 state=03 lifetime=0005
    Extended: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Log entry: 3
    Command 0: dc=02 sf=00 sc=01 sn=01 cl=00 ch=00 dh=a0 cmd=10 time=00d9cfc4
    Command 1: dc=02 sf=03 sc=0c sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9cfc4
    Command 2: dc=02 sf=03 sc=46 sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9cfc4
    Command 3: dc=02 sf=00 sc=10 sn=00 cl=00 ch=00 dh=a0 cmd=c6 time=00d9cfc4
    Command 4: dc=00 sf=00 sc=20 sn=5f cl=86 ch=29 dh=e2 cmd=c8 time=00d9cfc4
    Error: err=84 sc=00 sn=7e cl=86 ch=29 dh=e2 status=51 state=03 lifetime=0005
    Extended: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Log entry: 4
    Command 0: dc=02 sf=00 sc=01 sn=01 cl=00 ch=00 dh=a0 cmd=10 time=00d9d1b8
    Command 1: dc=02 sf=03 sc=0c sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9d1b8
    Command 2: dc=02 sf=03 sc=46 sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9d1b8
    Command 3: dc=02 sf=00 sc=10 sn=00 cl=00 ch=00 dh=a0 cmd=c6 time=00d9d1b8
    Command 4: dc=00 sf=00 sc=20 sn=5f cl=86 ch=29 dh=e2 cmd=c8 time=00d9d1b8
    Error: err=84 sc=00 sn=7e cl=86 ch=29 dh=e2 status=51 state=03 lifetime=0005
    Extended: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Log entry: 0
    Command 0: dc=02 sf=00 sc=01 sn=01 cl=00 ch=00 dh=a0 cmd=10 time=00d9d3ac
    Command 1: dc=02 sf=03 sc=0c sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9d3ac
    Command 2: dc=02 sf=03 sc=46 sn=00 cl=00 ch=00 dh=a0 cmd=ef time=00d9d3ac
    Command 3: dc=02 sf=00 sc=10 sn=00 cl=00 ch=00 dh=a0 cmd=c6 time=00d9d3ac
    Command 4: dc=00 sf=00 sc=20 sn=5f cl=86 ch=29 dh=e2 cmd=c8 time=00d9d3ac
    Error: err=84 sc=00 sn=7e cl=86 ch=29 dh=e2 status=51 state=03 lifetime=0005
    Extended: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
device error count: 11


Jukka Salmi --> netbsd-help (2005-01-11 16:07:36 +0100):
> Hi,
> 
> on a i386 system running -current (2.99.11) I'm using RAIDframe to mirror
> 60GB parts of two 80GB IDE disks. Both disks are new and recently installed
> because one of the old disks failed. Partial dmesg output of the system in
> question is show below.
> While doing heavy I/O, messages like the following are logged:
> 
> wd1a: error reading fsbn 35173280 of 35173280-35173311 (wd1 bn 35173343; cn 34894 tn 3 sn 2), retrying
> wd1: (aborted command, interface CRC error)
> wd1: soft error (corrected)
> 
> I remember seeing similar (at least for me) messages[1] whith the old
> disks in the same machine.
> 
> After a while, the kernel decides to downgrade wd1:
> 
> wd1a: error reading fsbn 36275744 of 36275744-36275775 (wd1 bn 36275807; cn 35987 tn 14 sn 29), retrying
> wd1: (aborted command, interface CRC error)
> wd1: transfer error, downgrading to Ultra-DMA mode 5
> wd1(viaide0:1:0): using PIO mode 4, Ultra-DMA mode 5 (Ultra/100) (using DMA)
> cd1(viaide0:1:1): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)
> 
> This is quite reproducible so far.
> 
> Hmm, does this look like a bad disk? Hints are appreciated!
> 
> 
> TIA, Jukka
> 
> [1] http://mail-index.netbsd.org/netbsd-help/2004/10/25/0006.html
> 
> NetBSD 2.99.11 (GENERIC) #0: Wed Dec 22 16:41:14 CET 2004
> 	build@himo.salmi.ch:/build/nbsd/sys/arch/i386/compile/GENERIC
> [...]
> viaide0 at pci0 dev 17 function 1
> viaide0: VIA Technologies VT8235 ATA133 controller
> viaide0: bus-master DMA support present
> viaide0: primary channel configured to compatibility mode
> viaide0: primary channel interrupting at irq 14
> atabus0 at viaide0 channel 0
> viaide0: secondary channel configured to compatibility mode
> viaide0: secondary channel interrupting at irq 15
> atabus1 at viaide0 channel 1
> [...]
> Kernelized RAIDframe activated
> atapibus0 at atabus0: 2 targets
> cd0 at atapibus0 drive 1: <ASUS    CD-S520/A, , 1.6K> cdrom removable
> cd0: 32-bit data port
> cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)
> wd0 at atabus0 drive 0: <HDS728080PLAT20>
> wd0: drive supports 16-sector PIO transfers, LBA48 addressing
> wd0: 78533 MB, 159560 cyl, 16 head, 63 sec, 512 bytes/sect x 160836480 sectors
> wd0: 32-bit data port
> wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
> wd0(viaide0:0:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA)
> cd0(viaide0:0:1): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)
> atapibus1 at atabus1: 2 targets
> cd1 at atapibus1 drive 1: <PLEXTOR CD-R   PX-W4012A, 438146, 1.05> cdrom removable
> cd1: 32-bit data port
> cd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)
> wd1 at atabus1 drive 0: <HDS728080PLAT20>
> wd1: drive supports 16-sector PIO transfers, LBA48 addressing
> wd1: 78533 MB, 159560 cyl, 16 head, 63 sec, 512 bytes/sect x 160836480 sectors
> wd1: 32-bit data port
> wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
> wd1(viaide0:1:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA)
> cd1(viaide0:1:1): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)
> raid0: RAID Level 1
> raid0: Components: /dev/wd0a /dev/wd1a
> raid0: Total Sectors: 120103040 (58644 MB)
> boot device: raid0
> root on raid0a dumps on raid0b
> root file system type: ffs
> [...]
> 
> -- 
> bashian roulette:
> $ ((RANDOM%6)) || rm -rf ~

-- 
bashian roulette:
$ ((RANDOM%6)) || rm -rf ~